Add openmax dl routines for review. MUST NOT BE LANDED

third_party/openmax_dl/dl/sp/src/omxSP_FFTInit_R_S32.c

+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ *
+ *  This file was originally licensed as follows. It has been
+ *  relicensed with permission from the copyright holders.
+ */
+
+/**
+ * 
+ * File Name:  omxSP_FFTInit_R_S32.c
+ * OpenMAX DL: v1.0.2
+ * Last Modified Revision:   7777
+ * Last Modified Date:       Thu, 27 Sep 2007
+ * 
+ * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
+ * 
+ * 
+ * Description: 
+ * Initialize the real forward-FFT specification information struct.
+ */
+
+#include "dl/api/armOMX.h"
+#include "dl/api/omxtypes.h"
+#include "dl/sp/api/armSP.h"
+#include "dl/sp/api/omxSP.h"
+
+
+
+/**
+ * Function: omxSP_FFTInit_R_S32
+ *
+ * Description:
+ * Initialize the real forward-FFT specification information struct.
+ *
+ * Remarks:
+ * This function is used to initialize the specification structures
+ * for functions <ippsFFTFwd_RToCCS_S32_Sfs> and
+ * <ippsFFTInv_CCSToR_S32_Sfs>. Memory for *pFFTSpec must be
+ * allocated prior to calling this function. The number of bytes
+ * required for *pFFTSpec can be determined using
+ * <FFTGetBufSize_R_S32>.
+ *
+ * Parameters:
+ * [in]  order       base-2 logarithm of the desired block length;
+ *                         valid in the range [0,12].
+ * [out] pFFTFwdSpec pointer to the initialized specification structure.
+ *
+ * Return Value:
+ * Standard omxError result. See enumeration for possible result codes.
+ *
+ */
+OMXResult omxSP_FFTInit_R_S32(
+     OMXFFTSpec_R_S32* pFFTSpec,
+     OMX_INT order
+)
+{
+    OMX_INT     i,j;
+    OMX_SC32    *pTwiddle,*pTwiddle1,*pTwiddle2,*pTwiddle3,*pTwiddle4;
+    OMX_S32     *pBuf;
+    OMX_U16     *pBitRev;
+    OMX_U32     pTmp;
+    OMX_INT     Nby2,N,M,diff, step; 
+    OMX_S32     x,y,xNeg;
+    ARMsFFTSpec_R_SC32 *pFFTStruct = 0;
+
+   
+    pFFTStruct = (ARMsFFTSpec_R_SC32 *) pFFTSpec;
+
+    /* if order zero no init is needed */
+    if (order == 0)
+    {
+        pFFTStruct->N = 1;
+        pFFTStruct->pTwiddle = NULL;
+        pFFTStruct->pBuf = (OMX_S32 *)
+               (sizeof(ARMsFFTSpec_R_SC32) + (OMX_S8*) pFFTSpec);
+        
+        return OMX_Sts_NoErr;
+    }
+
+    /* Do the initializations */
+    Nby2 = 1 << (order - 1);
+    N = Nby2 << 1;
+                    
+    
+    
+    pBitRev = NULL ;                /* optimized implementations don't use bitreversal */
+    
+    pTwiddle = (OMX_SC32 *) 
+        (sizeof(ARMsFFTSpec_R_SC32) + (OMX_S8*) pFFTSpec);
+        
+    /* Align to 32 byte boundary */
+    pTmp = ((OMX_U32)pTwiddle)&31;              /* (OMX_U32)pTwiddle % 32 */
+    if(pTmp != 0)
+        pTwiddle = (OMX_SC32*) ((OMX_S8*)pTwiddle + (32-pTmp));                
+        
+    pBuf = (OMX_S32*)        
+        (sizeof(OMX_SC32) * (5*N/8) + (OMX_S8*) pTwiddle);
+    
+    /* Align to 32 byte boundary */
+    pTmp = ((OMX_U32)pBuf)&31;                 /* (OMX_U32)pBuf % 32 */
+    if(pTmp != 0)
+        pBuf = (OMX_S32*) ((OMX_S8*)pBuf + (32-pTmp));                    
+                    
+        
+    
+    
+    /* 
+     * Filling Twiddle factors : exp^(-j*2*PI*k/ (N/2) ) ; k=0,1,2,...,3/4(N/2)
+     * N/2 point complex FFT is used to compute N point real FFT
+     * The original twiddle table "armSP_FFT_S32TwiddleTable" is of size (MaxSize/8 + 1)
+     * Rest of the values i.e., upto MaxSize are calculated using the symmetries of sin and cos
+     * The max size of the twiddle table needed is 3/4(N/2) for a radix-4 stage
+     *
+     * W = (-2 * PI) / N 
+     * N = 1 << order
+     * W = -PI >> (order - 1)
+     */
+    
+    M = Nby2>>3;
+    diff = 12 - (order-1);
+    step = 1<<diff;             /* step into the twiddle table for the current order */
+    
+    x = armSP_FFT_S32TwiddleTable[0];
+    y = armSP_FFT_S32TwiddleTable[1];
+    xNeg = 0x7FFFFFFF;
+    
+    if((order-1) >=3)    
+    {
+            /* i = 0 case */
+            pTwiddle[0].Re = x;
+            pTwiddle[0].Im = y;
+            pTwiddle[2*M].Re = -y;
+            pTwiddle[2*M].Im = xNeg;
+            pTwiddle[4*M].Re = xNeg;
+            pTwiddle[4*M].Im = y;
+            
+    
+        for (i=1; i<=M; i++)
+          {
+            j = i*step;
+            
+            x = armSP_FFT_S32TwiddleTable[2*j];
+            y = armSP_FFT_S32TwiddleTable[2*j+1];
+            
+            pTwiddle[i].Re = x;
+            pTwiddle[i].Im = y;
+            pTwiddle[2*M-i].Re = -y;
+            pTwiddle[2*M-i].Im = -x;
+            pTwiddle[2*M+i].Re = y;
+            pTwiddle[2*M+i].Im = -x;
+            pTwiddle[4*M-i].Re = -x;
+            pTwiddle[4*M-i].Im = y;
+            pTwiddle[4*M+i].Re = -x;
+            pTwiddle[4*M+i].Im = -y;
+            pTwiddle[6*M-i].Re = y;
+            pTwiddle[6*M-i].Im = x;
+        }
+        
+     
+    }
+    else
+    {
+        if ((order-1) == 2)
+        {
+            pTwiddle[0].Re = x;
+            pTwiddle[0].Im = y;
+            pTwiddle[1].Re = -y;
+            pTwiddle[1].Im = xNeg;
+            pTwiddle[2].Re = xNeg;
+            pTwiddle[2].Im = y;
+        
+        }
+        if ((order-1) == 1)
+        {
+            pTwiddle[0].Re = x;
+            pTwiddle[0].Im = y;
+        
+        }        
+        
+    
+    }
+    
+    
+    /*
+     * Now fill the last N/4 values : exp^(-j*2*PI*k/N) ;  k=1,3,5,...,N/2-1 
+     * These are used for the final twiddle fix-up for converting complex to real FFT
+     */
+     
+    M = N>>3;
+    diff = 12 - order;
+    step = 1<<diff;
+    
+    pTwiddle1 = pTwiddle + 3*N/8;
+    pTwiddle4 = pTwiddle1 + (N/4-1);
+    pTwiddle3 = pTwiddle1 + N/8;
+    pTwiddle2 = pTwiddle1 + (N/8-1);
+    
+    x = armSP_FFT_S32TwiddleTable[0];
+    y = armSP_FFT_S32TwiddleTable[1];
+    xNeg = 0x7FFFFFFF;
+    
+    if((order) >=3)    
+    {
+                        
+    
+        for (i=1; i<=M; i+=2 )
+          {
+            j = i*step;
+            
+            x = armSP_FFT_S32TwiddleTable[2*j];
+            y = armSP_FFT_S32TwiddleTable[2*j+1];
+            
+            pTwiddle1[0].Re = x;
+            pTwiddle1[0].Im = y;
+            pTwiddle1 += 1;
+            pTwiddle2[0].Re = -y;
+            pTwiddle2[0].Im = -x;
+            pTwiddle2 -= 1;
+            pTwiddle3[0].Re = y;
+            pTwiddle3[0].Im = -x;
+            pTwiddle3 += 1;
+            pTwiddle4[0].Re = -x;
+            pTwiddle4[0].Im = y;
+            pTwiddle4 -= 1;
+            
+        }
+        
+     
+    }
+    else
+    {
+        if (order == 2)
+        {
+            
+            pTwiddle1[0].Re = -y;
+            pTwiddle1[0].Im = xNeg;
+            
+        }
+                
+    
+    }
+     
+   
+    /* Update the structure */
+    pFFTStruct->N = N;
+    pFFTStruct->pTwiddle = pTwiddle;
+    pFFTStruct->pBitRev = pBitRev;
+    pFFTStruct->pBuf = pBuf;
+
+    return OMX_Sts_NoErr;
+}
+/*****************************************************************************
+ *                              END OF FILE
+ *****************************************************************************/
+